Field of the Invention
The present invention relates to an apparatus for testing an electrical component having a simulation unit for producing a simulation signal, a plurality of test units, and at least one electrical connecting device. The simulation unit and the plurality of test units are connected or connectable to each other in an electrically conductive fashion via the at least one electrical connecting device.
Description of the Background Art
An apparatus for testing an electrical component is frequently referred to as a “testing apparatus” or a “simulator system.”
An extremely wide range of embodiments of apparatuses for testing electrical components such as a control system for a motor vehicle or an automation unit are known from the conventional art and are primarily used in applied research, industrial development, and other application areas, in particular the fields of mechatronics, automotive applications, aerospace engineering, systems and process engineering, and other technical fields that require the execution of process control tasks. In this context, therefore, a “control system” can be understood to mean a technical apparatus that essentially can be used for measurement, control, and/or regulation. In the broadest sense, it is generally an electrical, for example program-controllable system that is usually referred to as a “control unit,” particularly in the field of automotive applications. In this regard, a control system is not restricted only to the system theory definition of a control, but is also usually used to carry out regulation procedures.
Apparatuses for testing a control system that are known from the conventional art frequently have a simulation unit for producing, measuring, and/or analyzing a simulation signal, a plurality of test units for connecting the control system, and at least one connecting device such as a bus bar or bus system. In the conventional art, there are known bus bars that have one or more electrical conductors that is/are separated from other electrical conductors by an insulator such as an insulating plastic and/or an air gap. In this case, the bus bar can be a component of a printed circuit board. A printed electrical conductor path of the printed circuit board can, for example, on the one hand be partially enclosed in plastic and on the other hand, can be partially insulated from other electrical conductors by an air gap. A connecting device can, for example, be provided with two separate conductors.
In such apparatuses, it is disadvantageous that parasitic properties of the connecting device interfere with and/or alter the simulation signals. In other words, the parasitic properties of the bus bar or bus system cause a distortion of the simulation, which in the end can result in an error-encumbered test of the control system. In this regard, test results can be distorted and lead to incorrect results.
For purposes of error simulation, many components can be connected to the connecting device, which promotes the distortion of test results. Parasitic capacitances increase with the number of components connected and can have an effect across various switch cabinets over which the apparatus is distributed. It can also be necessary for high currents to be supported in the connecting device, which is why sufficient conductor cross-sections and/or sufficient conductor path widths (e.g. in printed circuit boards) must be selected for the connecting device. Furthermore, the use of power semiconductors is on the rise; these have switching behaviors whose timing is defined in a comparatively precise way. Both of these approaches, i.e. conductor paths for high currents and power semiconductors, promote the occurrence of parasitic capacitances that can have an interfering impact on sensitive signals. As a rule, the parasitic capacitance of bus bars increases with the number of interconnected components.
An error simulation can be desirable both at the level of a single control unit and also at the level of the combination. In this context, the design of the apparatus must be adapted to the respective test. A generic test design is only possible to a limited degree since the design itself, particularly the connecting device, can further distort the test results. In addition, testing a plurality of separate control units simultaneously and independently of one another is only possible with such a design after a corresponding configuration. For example, components in different racks can be connected to produce a test setup.
In this case, simultaneous and independent error simulations in the different racks are not possible.
Examples of a rack include a switch cabinet or a so-called 19-inch cabinet. As a rule, a rack can include a plurality of so-called sub-racks, where the sub-racks can be embodied, for example, as so-called subassembly supports, for example, as so-called 19-inch subassembly supports.
Various simulation signals can be used for testing an electrical component. For this reason, signals that are to be conveyed via the connecting device can be almost arbitrarily embodied and range from small sensor signals, also referred to as “low-level” below to large actuator signals, also referred to as “high-level” below.
A conceptual assignment of sensor signals to the high-level or low-level categories can differ depending on the embodiment of the test device. For example, it is possible to define all signals that have a maximum electrical voltage amount Umax≤10 mV and/or that have a maximum electrical current amount of Imax≤10 mA for assignment to the group of low-level signals. An exemplary determination for the group of high-level signals can define that all signals that have a maximum electrical voltage amount of Umax≥5 V and/or that have a maximum electrical current amount of Imax≥100 mA must be assigned to the group of high-level signals.
In this illustrated example, the signals that are quantitatively larger than the low-level signals, but quantitatively smaller than the high-level signals are, according to the above mentioned exemplary determination, nevertheless assigned to the group of high-level signals. The high-level range and low-level range can in principle be arbitrarily defined, but the high-level range always has larger values (voltage, current, and/or power) than the low-level range.
As a rule, a technical separation of the signals according to high and low level is not practically possible, for example, because at the time of the project planning for the apparatus, the boundary conditions are not known or a temporary implementation of a short circuit of a high-level signal to the low-level signal is explicitly required for testing purposes, for example in order to use the testing apparatus to simulate, for an electrical component to be tested, appropriate technical boundary conditions in the event of an error.